Telephone system



C. W. KECKLER.

TELEPHONE SYSTEM. APPLICATION FILED MAR. 27, 1918.

1,387,271. Patented Aug. 9, 1921.

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CHARLES W. RECKLER, or NEWARK, NEW JERSEY, ssreNoR T0 WESTERN Ernomiuo COMPANY, INCORPORATED, on NEW YoRK, Y., A CORPORATION OF NEW,YO\RK.'

, TELEPHONE SYSTEM. 5

i Specification of Letters Patent. Patented A g-. 9 1921;

Application filed March 2'7, 1918. Serial No. 224,924.

1"0 a'ZZ whom it may concern:

Be it known that 1, CHARLES VJ. KECKLER, a citizen of the United States, residing at Newark, in the county of Essex, State of New Jersey, have in'vented'certain new and useful Improvements in Telephone Systems, or? which the following is a full, clear, concise, and exact description. I

This invention relates to telephone systems, and more particularly to trunking arra gements used between an intercoinmunirating system and an exchange. i

The principal object of the present invention is to provide a new and improved trunking arrangement between a plurality of associated stations and an outside station or exchange in which the trunk circuit can be held in substitution of telephone set. In accordance with this feature of the'invention, a locally energized electromagnetic means is provided to establish a bridging connection withthe trunk circuit, together with means to include and maintain said electromagnetic means energized over such bridgingconnection after establishment thereof.

Other objects and fez-itures of the invention will appear from consideration of the following description.

The drawing illustrates one embodiment ofthe present invention as applied to an intercoinmunicating system. There are shown three intercommunicating stations, each being provided. for serviceover-a trunk line common thereto leading to an exchange at which the jack 1.

oi keys is provided at each station to connect with other stations of the system andsuch stations as are equipped tor-trunk service will have a trunk key T, and Wlll also have a retaining key R if such station is alsolntended to be able to transfer a trunk call to other stations of the system havingtrunk service. The keys operate through alockplate 18 which locks any'depressed key,

except the retaining key R in intermediate 21, 21 of the trunk line.

another of the keys A, B, C, H or T. The key R is not locked by the platel8, and does not release any other keys inits operation.

It is normally open as shown, but when operated, 1t effects. the holding of the trunk circuit, as hereinafter explained. The remaining keys, with the exception of the trunk keys T and home keys H, have three. positions: the normal, as shown, the signaling or lowermost posltlon iii-which the first and second, and third and fourth contacts are engaged; andin which the thirdcontact engages the bus bar 19; and an intermediate position, which differs from signaling position only in that there is no engagement of the contacts of these keys with the bus bar 19. i The trunk keys T' and home keys I-I differ in that theyneed have only a normal and talking position, it being unnecessary for any ofitscontacts-toengage the bus bar 19. The plate l8lserves to lock any depressed key-in intermediate position until released by operation ot-another of their number;

The present invention will best be under stood from a description ofa'the actual operatlon in handling a trunk call. F or this purpose assume that the exchange operator has connected an outside lineto the jack lOandapplied exchange si 'naling current-to opcrate the signal 20, Thissignal is preferfably located close to'one of, the intercominunicatii'i'g stations, which it is desired to have answer trunk calls in general. As

shown, this is station A; and the; party thereahupon perceivingthat the signal 20 has operated; will depress. histrunk key '1 to intermediate position and remove his receiver 13 from the hook switch 14, thereby bridging that station across the. conductors Talking current for the trunk connection'issuppliedfbyn I talking battery at the exihange (not shown) on" plugging into the jack l0, and completes the talking circuit to station A on removal of the receiver and depression or key T o'lrelay. 25, conductor 21, 26, first and secand contacts of key T,-conducto1s27 and 28,

transmitter 12, receiver l3,hook switch 14,

conductors 29 and 30,"fourth and third con tacts of key T, conductors 31 and 21 to the tip contact 32 of jack 10 and thence to the other side of talking battery. The relay 25 is preferably made slower acting than relay 23 so that on closure of this circuit the relay 23 will operate to close a short-circuiting path about the relay 25 before the latter can operate. This shortcircuit starts at conductor 24, and extends through armature and alternate contact of relay 23 and conductor 33 to conductor 21 beyond relay 25.

The relative speed of these two relays is not however absolutely essential, since even should relayr25 operate first, relay 23 would still operate and on attracting its armature short-circuit relay 25, thereupon allowing it to return to normal position. Station A would thus be in talking connection with the outside line and could converse therewith. At the conclusionof the conversation, the party at station A, restoring the receiver to its switchhook, opens the alternate switchhook contact, thereby operating a disconnect signal associated with the connected cord circuit at the exchange as is usual in common battery exchange systems.

Should party A findstation B was desired, he would depress his retaining key B, thereby completing an actuating circuit for the holding relay 34. This circuit extends from signaling battery35of the intercominunirating system, conductors 36 and37, bus bar 19, contacts of key R, conductors 38 and 39, right-hand winding of relay 34, conductors 40 and 41 to the other side of battery 35. Relay 34 is thereby operated and closesa holding circuit across the trunk line 21 and 21 which derives its energizing current from the talking battery of the exchange at which the jack 10 is located. This circuit extends from conductor 21 before it reaches relay 23, and extends over conductor 42, front armature, alternate contact and left-hand winding of relay 34, normal contact and armature of relay 25, and conductor 44 to conductor 21.

The party. at station A would now depress the local key of the desired station, in

this case key B, to signaling position. This E. On hearinghis signal 15 the party at B would depress his home button H to intermediate position and remove his receiver from the hook switch, thereby connecting his transmitter and receiver to the line conductors thereofand completing a talking circuit therebetween, talking battery 17 being supplied to the circuit through the impedance coil 16 of station E and the conductors 45 and 46.

A would inform B of the trunk call and then hang up, severing his connection with B and'bei'ng free to make or receive other intercommunicating calls. B would keep his receiver off and depress his key T to intermediate position, thereby operating relay 25 over a circuit extending from the exchange talking battery through ring con tact 22, exchange end otconductor 21, conductor42, left-hand contact of relay 34, con.- ductor 47, armature and normal contact of relay 23 (thereby short-circuited), conductor 24, winding of relay 25 conductor 21, conductor 26 of station B,first and second contacts of key T, conductors 27, 28, transmitter, receiver and hook switch thereof, conductors 29 and 30, iourthand third contacts of key T, conductors 31 and 21 and tip contact 32 tot-he exchange talking battery. Re-

lay 25 is thereby operated, opening the holding circuit of relay 34, which thereupon re turns to normal, opening in turnthe short circuit about the relay 23, and including this relay in the circuit .just traced. "Relay 23 will be actuated thereby and shunt out relay 25, the armature-of whichwill thereupon return to normal, which places the trunk apparatus in the same condition that existed before the call was transferred. On compleing the circuit through relay 23, whereupon the system would be restored ,to normal con-, dition, as previously explained.

vVhen a trunk call is originated by an intercommunicating station, the trunk key T thereat is depressed to talking position and the receiver removed fI'Oll'rtllG hook, thereby completing a signaling circuit to operate the answering signal llat. the exchange. This circuit is identical. with the talking oirruit previously traced except that the answering signal 11 is ncluded in oncuit with the battery 50 through the normal 7 contacts of the conductors 48 and 49 of jack 10. The signal 11 is thereby actuated, and

the operator on plugging into the jack in answering would disconnect the signal 10 and battery from the trunk conductors 21 and 21 and substitute talking battery (not shown) therefor. On learning the party de sired, the operator would romplete the connection thereto and supervisethe call inthc' usual manner. The relay 23 would be energized on signaling the exchange, and also after the operator has connected therewith in answering and would remain in thiscon dition until the. calling subscriber completes conversation and hangs up his receiver as previously explained. j i What is claimedisa 1. In a telephone system, in combination, a

subscribers station, a trunk circuit to said ,aa m

station, a telephone set at said station adapted to be connected with-said circuit, a bridging connection adapted when established to hold said circuit in substitution of said telephone set, a plurality of sources of current,

and electromagnetic means initially energized by current from one of the sources to establish said bridging connection and maintained energized by current from another of the sources; the means hav ng a winding nhold said circuit in substitution of said telephone set, another source of current inde pendent of the trunk circuit, a relay energized by current from such other sourceto establish said bridging connection and having a winding included in said connection on establishment'thereof to maintain the relay energized by current from-the first'mentioned source to maintain saidbridging connectionn v 3. In a telephone system, in combination, a plurality of subscribers stations, atrunk circuit common to said stations, a telephone set at each station adapted to be connected with said circuit, a bridgingconnection adapted when established to hold said circuit in substitution of a telephone set, aplurality of sources of current, electromagnetic means initially energized by current from oneof the sources to establish said bridging connection and maintained energized by current from another of the sources; the means u u r p i source of current independent of the trunk having a winding included in saidconnection on establishment thereof to said bridging connection, and means to disable said bridging connection due to subsequent'connection'of one of the telephone sets with said trunk circuit.

1. In a telephone system, in combination, a plurality of subscribers stations, a'trunk circuit common to said stations, a telephone set at each station adapted to be connected with said circuit, a bridging connection adapted when established to holdsaid circuit in substitution of a telephone set, a plurality of sources ofcurrent, a relay initially I energized by current from one of the sources to establish said bridg ng connection and maintained energized by current from an.

other of the sources, said relay having awinding included in said connection en es-' I tablishmentthereor to maintain said bridging connection, and means to disable said bridging connection due to subsequent con- 7 .nection of one of the telephone sets with said trunk circuit. e

phone set at each station adapted 5. In a telephone system, in combination, a subscribers station, a trunk circuit incoming to said station, a telephone set at said station, means for connecting said telephone set with said trunk circuit, a key, a plurality of sources of current, a relay having va pluralityof windings initially energized by current from one of the sources upon the actuation of said key over a circuit including one winding thereof, and a bridging connection including another winding of said relay and another of the sources of current established due to energization, thereof for holding said trunk circuitin substitution of said telephone set. i i

6. In a telephone system, in combination, a plurality of subscribers stations, a trunk circuit common to said stations,a telephone set at each station adapted to be connected with said circuit, a bridging connection adapted when established to hold said circuit in substitutionoi'ia telephoneset, a plu rality of sources of current, electrcinagnetic means initially energized by current from one'of the sources to establishsaid bridging connection and having an energizing winding included in said connection on establishment thereof to maintain said bridging connection by current from th'efother of the sources, switching means at said stations to control the initialienergization off said electromagnetic means, and means to disable said bridging connection due to subsequent connection of one oi"; the, telephone sets, with said trunk circuit. p 7. In a telephone system, in combination,

a plurality of subscribers. stations,a trunk circuit common to said stations, a source of current associated with said circuit, a teleto be connected with said trunk circuit, a second circuit, a bridging connection adapted when established to, holdsaid trunk circuit in substitution of a telephone'set, a relay energized by current from. the second source to'estabcircuit for said relay established due to com- 'lish said bridging connection, and aloc'king.

I 8. In a telephonesystem, in combination,

a plurality of subscribers stations, a trunk clrcuit common, to "said stations, asource of current associated with said circuit, a tele- Vphone'set; at each station adapted to be con. .nected with said trunk circuit, a bridging connection adapted when established to hold i said trunk circuit in substitution of al t'elephone set, a second source ofcurrent, a relay energized by current from thesecond source to establish said bridging connection, a locking circuit for-saidrelay established uponthe completionof said bridging, connection and including said firstcsource of current,

switching meansto connect a telep hone'set with said trunk circuit, and a second relay operating due to actuation of the switching means to disable said locking circuit.

9. In a telephone system, in combination, a plurality of subscribers stations, a trunk circuit common to said stations, a source of said trunk circuit in substitution or" a telephone set, a second source of current, a relay energized upon the actuation of one of v with the first and short-circuited by the the holding keys by current from the second source, to establish said bridging connection across said. trunk circuit, a locking circuit established for said relay upon the encrgization thereof and including said rst cuit, a bridging connection adapted when established to hold'said trunk circuit in substitution of a telephone set, a second relay inoperative during the energization oi said first relay and operable to disable said bridging connection, electromagnetic means ini tially energized to GSCZLbllSlI said bridging connection and held energized through such connection due to establishment thereof,

switching means at said station to actuate said electromagnetic means, means to disable said first relay upon the subsequent dlsconnection of a telephone set from said trunk circuit, and means to actuate said second.v

relay due to subsequent connection of a telephone set wlth said trunk circuit to disable the bridging connect1on.

11. In a telephone system, in combination,

a plurality of telephone stations, a trunk circuit common to said stations, a telephone set at each station adapted to be connected to said trunk circuit, a relayassociated with said trunk-circuit and operated on association of a telephone set with said trunk circuit, a bridging connection adapted when established to hold said trunk circuit in substitution of a telephone set, a second relay inoperative during the energization of said first relay, switching means at a station,

electromagnetic means initially energized due to actuatlon of the swltchlng means to establish said bridging connect1on and held energized through such connection due to establishment thereof, means to disable said first relay due to subsequent disconnection.

ofa telephone set from said trunk circuit, means to prevent reenergization of said first relay while said electromagnetic means is energized, and means to actuate said second relay due to subsequent connection of a telephone set withsaid trunk circuit to disable the bridgingconnection.

12. In a telephone system, in combination,

a plurality of telephone stations,a trunk circuit common to said stations, a telephone set ateach station adapte-dto be connected to said trunk circuit, a first relay in series withsaid trunkcircuit andenergizeddue to connection of a telephone setwith said circuit, a second relay connected in series energization otthe first, a bridging connection adapted when established to hold said trunk circuit in substitutionoi'a telephone" set, switching means at said stations, electromagnetic means initially energized due to actuation of the switching means to estab lish said bridging connection and held ener gized through such connection due to establishment thereof, means for deenergizing said first relay due to subsequent disconnection of telephone set from'said trunk circuit, a short circuit about said first relay partially established by the energization of said electromagnetic means and completely established due to subsequent deenergi'zation of said first relay, and means to actuate said second relay due to subsequent connection of a telephone set with said trunk circuit to disable said bridging circuit and to deenergize said electromagnetic means. 1

13. In a telcphonesystem, incombination, a plurality of telephone stations, a trunk circuit common to said stations, a telephone set at each station adapted to be connected to said trunk circuit, a first relay in'series with said trunk circuit and energized due to connectionot a telephone se'twith said circuit, a second relay connectedinseries with the first and shoit-circuited by the jenergizm tion of the first, a bridging-connection adapted whenlestablishedto hold said trunk circuit in substitution of a telephone set, a key, a third relay initially energized due to actuation of the key to establish said bridging connection and held energized through said connection due to establ shment thereof, means*l'or de'energizing said first relay due to subsequent disconnection of tele phone set from said trunk circuit, a short circuit about saidfirst relay prepared by the of a telephone set with said trunk circuit to disable said bridging circuit and to deenergize said third relay.

14. i In a telephone system, in. combination,

telephone set of a station with the trunk circuit to prevent operation of said disabling means until after establishment of said bridging connection.

15. In a telephone system, in combination,

a plurality of subscribers stations, a trunk circuit common to said stations, means to operatively associate said stations with said trunk circuit, a bridging connection ar- 'anged on establishment to hold said circuit in substitution of a subscribers station, means for establishing said bridging connection, means for disabling said bridging connection, and means responsive to the op erative connection of a station with the trunk circuit to prevent operation of said disabling means until after establishment of said bridging connection.

16. In a telephone system, in combination, a plurality of subscribers stations, a trunk circuit common to said stations, means to operatively associate said stations with said trunk circuit, a bridging connection arranged on establishment to hold said trunk circuit in substitution of a subscribers station, means to establish said bridging connection, a relay to disable said bridging con- 'nection, a second relay responsive tothe operative connection of a station with the trunk circuit to prevent operation of said first relay, and means operated subsequent to the disconnection of said station from the trunk circuit and incident to the establish ment of said bridging connection to render said'second relay ineffectual to prevent subsequent operation of the firstrelay.

17. In a telephone system, in combination,

a plurality of subscribers stations, a trunk circuit common to said stations, means to operatively associatesaid stations with said trunk circuit, a bridging connection arranged on establishment to hold said trunk circuit in substitution of a subscribers station,

means to establish said bridging connection,

CHARLES W. KEGKLER. 

